Abstract

Ge-based devices, currently being pursued as replacement of their Si counterparts, typically contain a germanium oxide layer next to the substrate. Here we show using first-principles calculations that, in contrast to Si technology, hydrogenation and fluorination are not effective ways of passivating interfacial centers with a Gedangling bond (DB). Moreover, we identify DB geometries that differ from the structures and we find that the boundary has a higher atomic-scale roughness than the interface. These key differences in interface morphology and defect properties are consistent with experimental data.